Advanced automation/Increasing capacity automatically as required
A major advantage of having processes almost completely automated is that capacity can easily be scaled up. Just as the manufacturing and construction machinery can be repaired automatically, more manufacturing machinery can also be created by machine, as needed.
This capability means we will be able to do things that are simply not possible at the moment. Mega-scale engineering projects become feasible. If a task is complicated, tedious and a great effort we only need to design the system for the job and let it get on with it. Easier said than done of course. But as these systems become more sophisticated, so will the design tools used to create them. People will be able to interface with these complex systems at ever higher levels of abstraction (although there will be plenty of technically-minded who understand the lower levels too). It will be similar to high-level programming languages hiding the lower levels of code - the individual nuts and bolts will be like the zeros and ones of.